v148 · WebRTC · Web APIs

SDP Inspector

Parse and highlight SDP offer/answer text to find the m=application section that signals data channel negotiation. Generate real SDP from RTCPeerConnection with and without alwaysNegotiateDataChannels: true and compare the results.

Generate real SDP offers

Without alwaysNegotiateDataChannels (default) —

Click "Generate both" to create an SDP offer.

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With alwaysNegotiateDataChannels: true —

Click "Generate both" to create an SDP offer.

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Paste an SDP offer or answer to parse and highlight m=application:

Parse an SDP to see highlighted output.

With alwaysNegotiateDataChannels: true — m=application appears in every offer even before createDataChannel() is called. Data channels can be created at any time without renegotiation.

Without the option (default) — m=application only appears if createDataChannel() was called before createOffer(). If the remote peer tries to open a channel first, a full renegotiation is required.

implementation reference

Need the exact API surface, compatibility boundaries, errors, lifecycle, and source links? Read the matching gendn reference ↗